#define _CRT_SECURE_NO_WARNINGS 
#include<stdio.h>



struct S
{
	int n;
	int arr[];
};

int main()
{
	struct S* p = (struct S*)malloc(sizeof(int) + 20 * sizeof(int));
	if (p == NULL)
	{
		perror("malloc");
		return 1;
	}
	else
		for (int i = 0; i < 20; i++)
		{
			p->arr[i] = i + 1;
		}
	free(p);
	p = NULL;
	return 0;
}
